The present invention relates to a method for operating a longitudinally guiding driver assist system of a motor vehicle.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Longitudinally guiding driver assist systems are widely known in the state of the art. Such driver assist systems control the operation of the motor vehicle through automatic brake or acceleration interventions at least in part automatically. The simplest example for such a longitudinally guiding driver assist system is the so called speed control device (GRA), often also referred to as cruise control. In this case, a desired speed can be set on the driver side, which speed is then automatically maintained as accurately as possible by the driver assist system.
This concept is expanded by longitudinally guiding driver assist systems, which include a so called slave controller, and often are also referred to as ACC-systems (adaptive cruise control). Here, the speed is only adjusted to the speed desired by the driver if no vehicle driving in front was detected. For example, if a vehicle driving front is detected, in particular of course one which drives with a speed slower than the desired speed, a time gap to the vehicle driving in front is automatically maintained until the latter has disappeared and the speed can be adjusted to the desired speed again. Often, the follower mode of such an ACC-system is brought to the driver's attention by a corresponding backlit symbol.
Presently known ACC-systems can also handle curves possibly without interception by the driver when following a vehicle in front. When one approaches a curve at an excessive speed, he is normally decelerated by the vehicle driving in front, because the latter is also much too fast for the curve and has to decelerate manually. If the curve radius is very small, the ACC-control object, i.e. the vehicle driving in front, can drive out of the region of detection of the sensors and no longer be taken into account by the system, however, in most cases a sufficiently great lateral acceleration has built up in this situation, so that the curvature of the curve can be adjusted to on the basis of the lateral acceleration. This is possible, since the maximally possible speed of the motor vehicle is limited based on the lateral acceleration.
If however, the ACC-control object, i.e. the vehicle driving in front is already lost before the curve entry without an appropriate lateral acceleration having been built up, the ACC-system would accelerate before the curve, necessitating an interception by the driver. If one drives toward the curve in free drive or only with a speed control device, an interception is necessary as well.
It would therefore be desirable and advantageous to provide a method for operating a longitudinally guiding driver assist system and motor vehicle which allows driving through curves without intervention by the driver also without an automatically decelerating ACC-control object.